This invention relates to a metod of and an apparatus for preparing pure water by freezing raw water into an ice mass for elimination of impurities therefrom and subsequently heating the ice mass for melting to obtain the pure water for the convenient supply to the customers.
Recently, the demand for water has been greatly increasing despite a poor supply of water with the result of supplying water of inferior quality as drinking water for home use. To resolve many difficulties in obtaining pure water there have been proposed many methods for purification of water such as a chemical treatment process with an ion exchange, a biological treatment process by an aeration, a distillation process and a freezing process among which the freezing process is preferably adopted to prevent the propagation of bacteria in the water during storage.
In the conventional freezing process which is essentially used in converting sea water into fresh water, a refrigerant is blown into the sea water for instant freezing to obtain a mixture of ice flakes and salt water and then the ice is segregated from the salt water for subsequent washing and thereafter the ice flakes are melted to obtain fresh water. This conventional process is effective for the continuous purification of water, notwithstanding the fact that the device for removing the salt component from the surface of the ice becomes complicated.
The inventor, after intensive studies to provide a convenient way to obtain purified water, has discovered a simple system for supplying purified water which comprises the steps of circulating the raw water into an ice making mechanism for freezing to obtain an ice mass with elimination of impurities, removing the formed ice mass from the ice making mechanism with washing, harvesting the resultant ice in a receptacle having a heating means for melting all or a part of the ice into the desired pure water, leading the pure water together with a part of the ice to a water tank to retain the water tank at a desired low temperature and supplying a desired amount of the pure water from the water tank through a valve means.